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Jointly developed SwRI-NASA software program earns R&D 100 Award

San Antonio -- September 26, 2003 -- A software program developed jointly by Southwest Research Institute® (SwRI®) and NASA Johnson Space Center for analyzing metal fatigue and fracture has been selected to receive a 2003 R&D 100 Award. The winning entry is the NASGRO® 4.0 Fracture Mechanics and Fatigue Crack Growth Analysis Software.

The R&D 100 Awards, sponsored by R&D Magazine, recognize the 100 most significant technical accomplishments of the past year. The awards will be presented in Chicago on October 16.

NASGRO 4.0 was developed by SwRI and NASA under a 2000 Space Act Agreement and is based on a code developed by NASA beginning in the 1980s. Originally called NASA/FLAGRO, the code was designed to provide fracture control analysis for manned space programs.

NASGRO calculates the crack growth rate and remaining structural life of components undergoing cyclic loading and also calculates the conditions, such as loads and crack sizes, that cause failure by fracture.

"The three fundamental challenges of fracture mechanics analysis are calculating the driving force for crack growth, known as the stress intensity factor, characterizing the material properties that describe the resistance to crack growth, and developing accurate crack growth algorithms that account for the effects of load history," said SwRI Senior Program Manager Dr. Craig McClung, a principal developer of NASGRO 4.0.

The NASGRO stress intensity factor library contains more than 50 standard solutions to permit more accurate modeling of the geometry and stress field. The code has a massive material property database that comprises 476 metallic materials, 3,000 sets of fatigue crack growth data, 6,000 fracture toughness data points and statistically derived crack growth equations for nearly all the materials.

NASGRO executes on all Windows® and many Unix® platforms and has an intuitive graphical user interface that guides the user through a series of screens in which geometry, material properties and load history are specified before a final screen provides analysis output.

The Institute first became involved with developing the code in the mid-1990s. Steady growth in the capabilities of NASGRO and an increase in the number of users prompted a new vision for the code. Under the Space Act Agreement, NASA and SwRI became joint developers.

NASGRO 4.0 is the first commercial version of the code. NASA has granted the copyright for NASGRO 4.0 to the Institute, which permits SwRI to license the code to consortium participants and others. Government agencies that actively support the code - NASA, FAA and the European Space Agency - retain perpetual royalty-free license for their employees and contractors.

"NASGRO continues to be improved through the coordinated efforts of NASA and SwRI," McClung said. Version 4.1 is currently in test release, and Version 4.2 is scheduled for release in 2004, with several major improvements.

SwRI formed the NASGRO consortium, a group of 14 major companies from nine countries, including major manufacturers of space structures, aircraft, rotorcraft and gas turbine engines. The consortium recently completed the second year of an initial three-year term. Renewal for an additional three years is planned in 2004, and new consortium participants are welcomed. SwRI also licenses NASGRO 4.0 for a fee to both individual users (single seat licenses) and organizational users (site licenses) outside the consortium.

Another SwRI invention, the Virtual Vehicle Transmission Test Cell, also won a 2003 R&D 100 Award. The VVTTC simulates gasoline engines and vehicles around a transmission for product development and performance verification, eliminating the need for traditional on-track vehicle testing.

For information about NASGRO and the NASGRO consortium, and links to information about other integrity and reliability software and research at SwRI, visit the NASGRO web site at or

For more information, contact Deborah Deffenbaugh, Communications Department, (210) 522-2046, Fax (210) 522-3547, PO Drawer 28510, San Antonio, TX 78228-0510.

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